The present invention relates to a disk drive for recording information on a magnetic disk or an optical disk, and specifically, to a dust proof structure for such a disk drive.
Conventionally, disk drive are formed by enclosing with a cover a main body of a disk drive mechanism including an information recording disk on which information is recorded or from which the information is reproduced.
The main body of the disk drive has a frame unit on which parts are mounted for receiving the information recording disk.
Referring to the magnetic disk, the frame unit has a box form comprising a bottom plate, right and left side walls and a rear wall which are formed in one body from the same one plate. The rear portion extending from the rear wall of the frame unit is covered by a rear plate. In the frame unit, there is provided a disk holder unit for receiving the information recording disk. A recording and reproducing head for recording and reproducing information on and from the disk is provided at one end of the holder unit and the vicinity of one end of the frame unit so as to be able to contact or closely access the disk received therein. The recording and reproducing head and some other parts are mounted on a carriage assembly which is a mechanism for moving the head close to or away from the disk. Further, at the rear part of the frame unit, there is provided a stepping motor having a leadscrew shaft for moving the recording and reproducing head in the radial direction of the disk. The stepping motor is mounted outside of the rear wall of the frame unit and the shaft of the leadscrew shaft extended through the rear wall into the frame unit.
A drive assembly for rotating the disk received in the holder unit is provided beneath the holder unit. The drive assembly is introduced through the bottom wall via a rotor of a D.C. motor integrally mounted on a print circuit board provided outside of the bottom wall of the frame unit.
In the mean time, in the conventional disk drive, a bezel is provided at the front part of the frame unit the side walls of which are enveloped by the cover. On the rear wall, however, there are formed holes for mounting or connecting of parts and unavoidable spaces owing to press works. For example, a pair of fixing members for supporting the print circuit board for driving the stepping motor at outside part of the bottom wall of the frame unit are formed by punching the both sides of the rear wall. At the back side of the disk drive, the rear plate is provided for covering the upper surface of the portion backside of the rear wall.
At the rear part of the print circuit board for driving the stepping motor and the recording and reproducing head, on the other hand, a connector for connecting the circuit to outside devices is provided. Accordingly, an outer case enclosing the frame unit necessarily has an opening at its rear part for connection with the connector. There has been, thus, a problem that dust comes into the frame unit through the spaces or holes on the rear wall of the frame unit as described above. In particular, there are the carriage assembly having the recording and reproducing head or other precision parts at the vicinity of the rear wall of the frame unit. The carriage assembly and precision parts, therefore, tend to operate erroneously owing to the dust. There is another problem that data recorded on the disk are destroyed because the recording and reproducing head presses the dust on the disk.